Re: dumb as a rock

["Robert Green" <ROBERT_GREEN1963@xxxxxxxxx>]

"RF Dude" <post@xxxxxxxxxxxxxxxxx> wrote in message
news:Q9JXe.5346$0u2.774079@xxxxxxxxxxxxxxxxxxxxxxxx
> Just how conductive is concrete?  Can its conductance be improved?

Your friend Google

http://www.google.com/search?q=conductivity+concrete

led quickly to:

http://journalsip.astm.org/JOURNALS/CEMENT/PAGES/37.htm

a "scholarly" site cite that suggests it's all about slag:

Abstract
Electrical conductivity measurements were made on concrete systems
containing blast-furnace slag. It was found that the slag content
significantly influenced the concrete conductivity. A linear relationship
between the concrete conductivity and the slag content and the volume
fraction of aggregate was established by experiment. The relationship can be
expressed as follows sc = ka·fa + ks·(?slg&den;c) + kowhere sc is the
concrete conductivity; fa is the volumetric fraction of aggregate; (slg/c)
is the relative content of slag by weight of cementitious materials; and ka,
ks, and ko are empirical coefficients. This relationship provides a basis
for the determination of slag content in hardened concrete by electrical
conductivity methods.

Keywords:
blast-furnace slag, concrete, electrical conductivity, portland cement

******************************************

I like the word cementitious.  Might be a good synonym for block head or the
phrase, dumb as a rock.

Now if you're into "interfacial zone thickness" then you might want to look
at:

http://ciks.cbt.nist.gov/~garbocz/appendix1/node18.html

It's pretty scholarly, too.  :-)

http://ciks.cbt.nist.gov/

Is the Virtual Cement and Concrete Testing Laboratory of the National
Institute for Standards and Technology, Building and Fire Research
Laboratory.

--
Bobby G.